UTILISATION D’UN SYSTÈME D’INFORMATION GEOGRAPHIQUE DANS LA MODELISATION D’UN BASSIN VERSANT

The modeling of the Samson River’s watershed is made through the coupling of the geographical information system (GIS) SPANS with a hydrological model. The Samson River, a tributary of the Chaudiere River for which a SPANS database already exists, possesses the required characteristics for the study: a small, natural and ungauged watershed. After a close look at existing and easily available hydrological models, it appears that none were appropriate due to their inability to take advantage of the GIS capabilities and because their use is too complex for the scope of this study. Thus, a hydrological model is built up from an existing two-dimensional routing algorithm modified to include hydrological parameters. The algorithm discretizes the watershed as a rectangular grid and uses a digital elevation model and the SCS curve numbers approach to compute the contributing areas. These contributing areas are indicators of discharge and can be used with the time to peak to construct a hydrograph of a rain event....